1. Field of the Disclosure
The disclosure relates to microbial growth prevention methods and more particularly pertains to a new mold and fungal growth prevention method for preventing the growth of molds and fungi on liquid water treatment dispersant.
2. Description of the Prior Art
Water treatment systems have consistently struggled with a safe and effective way to sequester iron, manganese and calcium in water systems. Water systems have used polyphosphates in the past for the prevention and removal of particular compounds such as calcium carbonate, calcium sulfate, iron and manganese oxides as well as heavy elements such as barium and strontium. Typically the water treatment industry has desired to increase the phosphate content of their treatments in order to control these compounds and elements, but concerns over increasing levels of phosphates in rivers and aquifers has increased the back end cost of removing phosphates before it can be discharged to rivers and streams. Moreover, there has been a general consensus that lowering the phosphate concentrations within waterways is a favorable outcome. Consequently there has been a search for a water treatment compound which will provide the benefits of high control without increasing the amount of phosphates added to the water.
One particularly useful product for this is Polysperse which is a dispersant and phosphate stabilizer made and sold by Pacific Standard Specialties, Inc., located at 14205 Arizona 188, Globe, Ariz. Polysperse, having CAS No. 71050-62-9, is a homopolymer having phosphonate and polyacrylate characteristics and more specifically comprises a poly (acrylic acid-co-hypophosphite) sodium salt. While this product not only sequesters the selected compounds and elements as desired with lower amounts of phosphates than comparable treatment solutions, it has the added benefit of greatly extending the time that iron and manganese are maintained within solution such that neither will precipitate out of the water. This product typically comes in a liquid form and is simply added to water being treated in a conventional manner.
However, a concern has arisen over dispersants such as Polysperse due to their inability, in their usually provided formulations, to prevent the growth of molds, fungi and bacteria. Such growth typically occurs on the surface of the dispersant and has many negative aspects. One problem with molds and fungi growing on the liquid is that it is a precursor for bacterial growth. As can be well appreciated, one would not want to add molds, fungi or bacteria to water being treated as one of the objectives of such treatment is to remove these elements from the water. A second problem is that the molds, fungi and bacteria are utilizing the dispersant as a food source and are therefore necessarily breaking it down and rendering it less effective. This in turn leads to higher costs as additional dispersant will be required for the treatment process. Finally, the growth of these microorganisms on the dispersant is aesthetically unpleasant causing treatment operators to question the quality of the product and lowering their desire to use it.
Multiple possible solutions have been tested to alleviate the above problems but most have not succeeded in their purpose of preventing growth of the microorganisms while simultaneously being economical and non-detrimental to the efficacy of the dispersant product. For example, it was believed that the pH of the product could be lowered to such a point that growth would be inhibited, but it was found that the addition of acids increased the cost of the product above a useful range. Alternatively, it was believed that raising the pH, above 6.0 for example, would also prevent growth. However, raising the pH caused precipitation of existing phosphates and therefore was not feasible. Different additives were also considered such as sodium silicate but the levels at which it could economically be added did not prevent growth as needed. Potassium had similar drawbacks as sodium. Phosphates could be added in the form of sodium phosphates but this would of course counter the goal of using less phosphate. of those compounds. Thus, there still is a need for a method or mixture which provided all of the benefits of the product's ability to sequester and scale remove while preventing the growth of the microorganisms discussed above.